Expediting redox kinetics of sulfur species by atomic-scale electrocatalysts in lithium–sulfur batteries

Lithium–sulfur (Li–S) batteries have extremely high theoretical energy density that make them as promising systems toward vast practical applications. Expediting redox kinetics of sulfur species is a decisive task to break the kinetic limitation of insulating lithium sulfide/disulfide precipitation/dissolution. Herein, we proposed a porphyrin-derived atomic electrocatalyst to exert atomic-efficient electrocatalytic effects on polysulfide intermediates. Quantifying electrocatalytic efficiency of liquid/solid conversion through a potentiostatic intermittent titration technique measurement presents a kinetic understanding of specific phase evolutions imparted by the atomic electrocatalyst. Benefiting from atomically dispersed “lithiophilic” and “sulfiphilic” sites on conductive substrates, the finely designed atomic electrocatalyst endows Li–S cells with remarkable cycling stablity (cyclic decay rate of 0.10% in 300 cycles), excellent rate capability (1035 mAh g⁻¹ at 2 C), and impressive areal capacity (10.9 mAh cm⁻² at a sulfur loading of 11.3 mg cm⁻²). The present work expands atomic electrocatalysts to the Li–S chemistry, deepens kinetic understanding of sulfur species evolution, and encourages application of emerging electrocatalysis in other multielectron/multiphase reaction energy systems.